In addition to transistors, resistors, capacitors, and diodes, semiconductor devices also often contain fuses. These fuses may be used for several purposes. For example, fuses may be used within semiconductor devices for purposes of introducing or deleting customized circuit elements into a semiconductor device. In addition, fuses within semiconductor devices may be used for purposes of severing a non-operative portion of the semiconductor device and replacing that non-operative portion with a redundant semiconductor device fabricated on the same semiconductor substrate. Fuse elements may also be used to provide direct alternative current (DAC) trimming.
Selected fuses are usually blown by either a laser beam, or an electrical current, depending on the design of the fuse/device. In an electrical fuse design, electronically programmable fuses are blown by passing a current through the fuse link. The electrical current then causes a permanent change to the resistance of the fuse. The fuses that are blown are selected by one or more programming methods, which are generally known to those skilled in the art. Electronically programmable fuses, also called eFuses, have become popular because of the circuit and systems design flexibility that they provide. The eFuse can be programmed even when the chip is mounted in the package and installed in the system. For example, users can tailor a design to the specific needs of an application after the product is installed. The eFuse also enables the freedom to alter the design, or fix problems that may occur during the life of the product.
While eFuses are thus desirable within semiconductor device design and fabrication and provide an essential tool for cost effective and efficient semiconductor device design and fabrication, eFuses are not entirely without problems. In particular, as semiconductor device dimensions circuit, and in turn, operating voltages, have decreased, it has become increasingly more difficult fabricate eFuses that are susceptible to comparatively low severing, (i.e., programming) current at typical severing voltages of less than approximately 3 volts. Accordingly, it may be desirable to overcome the deficiencies and limitations described hereinabove.